An anisotropic conductive film constituted by conductive particles and a binder resin composition as a dispersion medium for the particles has been widely used as an electrical connection material during mounting an electronic component such as an IC chip on a substrate. The anisotropic conductive film requires high adhesion strength. Therefore, an epoxy-based adhesive composition capable of achieving higher adhesion strength than that of an acrylate-based adhesive composition has been widely used as the binder resin composition. Such an epoxy-based adhesive composition is generally a composition in which an anionic curing agent or a cationic curing agent is mixed with an epoxy compound.
In an anisotropic conductive film using the epoxy-based adhesive composition as the binder resin composition, a cured product of the epoxy-based adhesive composition cannot sufficiently relax a stress generated at an anisotropic conductive connection portion by curing shrinkage of the epoxy-based adhesive composition. Therefore, such a cured product of the epoxy-based adhesive composition has a problem in which the anisotropic conductive connection portion may be warped. As a countermeasure, there has been a proposal in which a radically polymerizable acrylate composition giving a cured product having relatively more excellent stress relaxation performance than that of an epoxy-based adhesive composition containing a cationic curing agent is mixed in the epoxy-based adhesive composition to impart the stress relaxation performance without decreasing high adhesion strength of the epoxy-based adhesive composition (Patent Literature 1).